Supplemental Equity and Comprehensive Income Information (Details 3) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Components of Comprehensive Income (Loss) Attributable to 3M
Net income attributable to 3M	$ 1,161	$ 1,088	$ 3,453	$ 3,329
Cumulative translation	380	(489)	211	(63)
Tax effect	21	(18)	(1)	29
Cumulative translation - net of tax	401	(507)	210	(34)
Defined benefit pension and postretirement plans adjustment	153	120	460	358
Tax effect	(57)	(43)	(169)	(152)
Defined benefit pension and postretirement plans adjustment - net of tax	96	77	291	206
Debt and equity securities, unrealized gain (loss)	4	(3)	6	(8)
Tax effect	(1)	1	(2)	3
Debt and equity securities, unrealized gain (loss) - net of tax	3	(2)	4	(5)
Cash flow hedging instruments, unrealized gain (loss)	(57)	85	(44)	59
Tax effect	21	(31)	16	(22)
Cash flow hedging instruments, unrealized gain (loss) - net of tax	(36)	54	(28)	37
Comprehensive income (loss) attributable to 3M	1,625	710	3,930	3,533
Reclassification to earnings from accumulated other comprehensive income including noncontrolling interest that related to pension and postretirement expense in the income statement, before tax	153	117	460	355
Reclassification to earnings from accumulated other comprehensive income including noncontrolling interest that related to pension and postretirement expense in the income statement, after tax	96	77	291	207
Reclassification to earnings from accumulated other comprehensive income to gain (loss) on debt and equity securities in the income statement, before tax		(4)	(1)	(2)
Reclassification to earnings from accumulated other comprehensive income to gain (loss) on debt and equity securities in the income statement, after tax		$ (2)	$ (1)	$ (1)